Long use of chemical fertilizers and pesticides is known to deplete soil of beneficial organisms and leads to lower soil quality. Plants grown in such soils do not grow at the optimum rate or mass and yields are lower. Additionally, such plants may be at higher risk of infection and have lower immune-type responses to pests.
The size and activity of soil microbial communities are indicators of soil health, quality and fertility necessary for sustainable agriculture (Doran and Parkin, 1994; Kennedy and Papendick, 1995; Warkentin, 1995; Sparling, 1997). These communities have been classified into eubacteria, cyanobacteria, actinomycetes, archaebacteria, fungi, microalgae, protozoa, viruses, and some nematodes (Paul and Clark, 1989; Sims, 1990; Roper and Gupta, 1995). Out of these groups, microalgae perform several important functions for agro-ecosystems and can also function as a bio indicator for soil quality.
What is needed are methods and compositions comprising microalgae that can be used for treating or amending soil.